Conductive footwear



April 7, 1942. A. SIERS CONDUCTIVE FOOTWEAR Filed March 22, 1941 fihm nyinto: "M

Patented Apr. 7, 1942 UNITED STATES PATENT OFFICE 2,279,094 coNnUo'rIvEFOOTWEAR Anthony Siers, Humboldt, Tenn., assignor to O'Donnell ShoeCompany, Humboldt, Tom, a corporation of Minnesota Application March 22,1941, Serial No. 384,743

The present invention relates to conductive 3 Claims.

footwear and more particularly to an insole designed for use inconnection with conductive shoes and other articles of footwear whereinthe outer sole, or at least an effective portion thereof, is of aconductive nature.

Footwear of the character set forth above and which is of a conductingnature is so designed that static electrical charges are not readilygathered by the human body. Furthermore,

such electrical charges, if gathered, are prac-.

tically instantaneously discharged through the shoe or other article offootwear directly to the supporting surface which constitutes anelectrical ground or discharge body for the condenser action of thehuman body. Thus thistype of footwear is found useful by surgeons,nurses and other attendants in operating rooms where the fumes of etheror other combustible vapors or ases are apt to be present. I

Footwear of this character is also useful in certain industrial tradessuch as in' powder plants and other places where explosives aremanufactured as well as in gunnery turrets or powder magazines on boardwarships and in other places where extreme caution is required toprevent accumulation and accidental discharge of static methods forrendering leather and even rubber sole-forming materials conductive toprovide a leakage path between the foot of the user and the supportingsurface. In either case, in order to establish proper electricalconnection between the foot of the user and the outsole, direct contactbetween the foot and outsole has been reelectrical charges'from thehuman body or from the clothing worn thereby.

Theimproved insole comprising the present invention is possessed ofconducting features as will be set forth in detail hereinafter and isadapted to establish electrical communication or create a conductingelectrical path between the foot of the user and the conducting outsoleof the particular shoe or other article in which the insole isinstalled, regardless of whether this latter outsole is of a conductingnature throughout, or whether it is only partially so as in the "casewhere metal or other conducting inserts are provided through theoutsole. In either case, the improvedinsole may, with or withoutmodification, be designed to establish the proper electricalcommunication between the foot of the user and the outsole and tootherwise serve the purposes for which it is intended.

Heretofore, various types and forms of conductive footwear have beendevised for establishing an electrical path between the foot of the userand the ground. Earlier attempts to render footwear conductive havedealt with the provision of metallic plugs that extend through the soleof the shoe for making simultaneous contact with the body and thesupporting surface.

More recent attempts have resulted in various sorted to.

In the case where metal inserts are employed, the discomfort afforded bya direct skin-tometal contact is too well known to require elaboration.Furthermore, the omission of an insole for the purpose of securing suchdirect electrical contact between the foot of the user and the outsolehas resulted in the dispensing with the various functions of an insoleand principal among which are the protection offered to the foot and tothe shoe against perspiration, the comfort of the user, the reinforcingand stiffening action of the insole, the appearance of the shoe asmarketed, etc.

Accordingly, the principal object of the pres-- ent invention is toprovide an insole for conductive shoes and other similar articles offootwear which will offer to the user of the shoe all the advantages ofthe ordinary insole while at the same time insuring proper electricalconnection (1. e., an electrical leakage path) between the foot and theconductive outer sole of the shoe regardless of the specific nature ofthe latter.

Another object of the invention is to provide such an insolein which themajor portion of the foot engaging surface area thereof is of anonconduoting nature thus imparting a maximum degree of comfort to theuser.

A still further object of the invention is to provide an insole havingassociated therewith a stiffening member of metal which, during usetricity originating in the human body are con- I ducted to a source ofgroundpotential.

Y t another object of the invention is to provide an insole possessingconductive features and which resembles the ordinaryinsole and is notunduly thick thus rendering it useable in the ordinary manner .ofinsoles and without making it necessary to enlarge the size of the shoewith which it is associated.

A further object of the invention is to provide 1e multiple piece insolepossessing conductive feaures. I

The provision of a multiple piece insole possessing conductive featuresand which is of compact unitary construction; one which is rugged anddurable; one which presents to the foot of the user no obstructions orprojections which would tend to render the shoe or other article inwhich it is installed uncomfortable; one which can be manufacturedeconomically; and one which is well adapted to perform the servicesrequired of it, are further desirable features that have been borne inmind in the production and development of the present invention.

Other objects and advantages of the invention, not at this timeenumerated, will become apparent as the nature of the invention isbetter understood.

In the accompanying single sheet of drawings forming a part of thisapplication:

Figure 1 is a top plan view of a conductive insole manufactured inaccordance with the principles of the present invention.

Figure 2 is a bottom plan view thereof.

Figure 3 is a sectional view taken longitudi nally through the insole ofFigures 1 and 2 and showing the same operatively associated with a shoehaving a conductive outsole, and

Figure 4 is a sectional view taken substantially along the line 4-4 ofFigure 1.

In all of the above described views, like characters of reference areemployed to designate like parts throughout.

Referring now to the drawing in detail, the

conducting insole is designated generally at I and includes an insoleproper in the form of a strip l2 of leather or other suitablenonconducting material having a peripheral contour conforming to theshape of the shoe M or other article of footwear in which the insole isinstalled.

The strip I2 includes a ball portion 16 and a rear heel portion l8connected together by an arch portion 20.

Extending around the sides of the arch portion 20 and around the sidesof the ball portion l6 and overlapping the edges thereof is a welt 22.This welt 22 is secured to the underneath side of the strip I2 by meansof stitching 24 although it is obvious that other securing means may beemployed if desired. The rear ends of the welt 22 terminate in theregion of the insole proper which is adjacent the juncture between theconnecting arch and heel portions l8 and 20.

A comparatively extensive opening or cut-away portion is formed in theball portion l6 of the insole proper in the medial region thereof andthis opening 30 is generally of rounded triangular configuration. Theopening 30 is closed by means of a conductive insert 32 (see also Figure4) which terminates substantially flush with the upper surface of theinsole proper. The insert 32 is of somewhat greater thickness than thethickness of the insole proper and is formed with a marginal flange 34which underlies the edges of the opening 30 and which extends laterallybeyond those edges to the inner edge of the welt 22.

The insert 32 may be formed of any suitable conducting material such asleather or other composition which has been treated chemically to renderthe same conducting. However, it is preferred that the material of theinsert 32 be formed of conductive rubber on account of the softness andelasticity of the latter and on account of the waterproofing and otherphysical properties which render it suitable for use in connection witharticles of footwear. Irrespective, however, of the specific material ofwhich the insert 32 may be formed, the essential features of theinvention are at all times preserved.

The heel portion of the insole proper is like- (ill wise formed with anopening 50 centrally there of and this latter opening may be of circularcontour. A conductive insert 52 is disposed in the opening 50 andterminates flush with the upper surface of the insole. The insert 52 isslightly thicker than the insole and a peripheral flange 54 underliesthe edges of the opening 5!]. The material of the insert 52 ispreferably the same as the material of the insert 32 and both insertsmay be received in their respective openings by a forced fit or bycementing or the like.

An arched stiffening piece Ell which is preferably formed of metal issecured to the insole proper on the underneath side thereof andunderlies and contacts a portion of the underneath surface of the insert52. The specific securing means employed for this purpose may be in theform of rivets 62 or the like which are preferably situated adjacent theopening 50. The stiffening piece extends forwardly along and is free ofthe arch portion of the insole proper and overlaps the rear portion ofthe insert 32 and contacts the latter thus establishing a directconductive path of low resistance between the inserts 32 and 52.

When the insole is installed or incorporated in a shoe or other articleof footwear as shown in Figure 3, a layer of a conductive fillermaterial 65 is applied to and substantially covers the underneath sideof the ball portion of the assembled multiple-piece insole Hi. Thisfiller material is in intimate contact with the underneath side of theball portion l6 of the insole proper and of the conductive insert 32.The welt 22 which, in effect forms a raised marginal ridge extendingaround the forward and side edges of the insole proper serves to confinethe conductive filler material to an effective area of the insole.

Substantially the entire upper surface of the strip l2 as well as theupper surfaces of the inserts 32 and 52 may have secured thereto by asuitable adhesive, a sock lining 66 which is forined of a conductivematerial such as conductive rubber, or leather which has been treated torender the same conductive. The socl: lining 66 being in intimatecontact with both inserts 32 and 52 serves to establish a permanent highresistance conductive path between the two inserts.

Inasmuch as the sole of the shoe with which the conductive insole isincorporated is of a conductive nature, an electrical connection betweenthe insert 52 and the sole is effected by direct contact between theseparts as well as by the direct contact of the insert with the stiffeningmember 60 which bears against the sole proper of the shoe. Electricalcommunication between the insert 32 and the sole of the outer shoe isobtained by conduction of electrical charges through the conductivefiller material 55.

It will be seen from the above description that in actual use of thepresent insole, electrostatic charges gathered in the human body will beconducted safely to the ground either through the opening 38 adjacentthe ball of the foot or the opening 50 adjacent the heel of the foot bymeans of the inserts 32 and 52 which are exposed to the foot throughthese openings, and which make electrical contact with the conductivesole of the outer shoe with which the insole is incorporated. The termrelatively soft as used herein is applicable to conductive rubber andleather or other similar material which has been rendered conductive bya suitable processing operation. Such a term is designed to distinguishthe conductive material used in both the inner and outer soles fromharder and more rigid materials such as metal which are perfectconductors and, unlike these softer materials, do not afford a slowleakage path for static electrical charges to the ground.

The invention is not to be limited to the exact arrangement of partsshown in the accompanying drawing or described in this specification asvarious changes in the details of construction may be resorted towithout departing from the spirit of the invention. Only insofar as theinvention has particularly been pointed out in the accompanying claimsis the same to be limited.

What is claimed is:

1. A conductive shoe comprising a conductive outsole designed for directcontact with the ground, said outsole being formed of relatively softflexible material which presents a relatively high resistance to staticelectrical charges, an insole substantially coextensive with the innerface of said outsole, said insole comprising a strip of relativelysoftmaterial including a ball portion, a heel portion and a connecting archportion, there being openings extending completely through the ball andheel portions of said strip respectively, and an insert of relativelysoft flexible conductive material disposed in each of said openings,said inserts also presenting a relatively high resistance to staticelectrical charges and conductively connected to said outside wherebysuch charges are slowly and without an attendant spark conducted fromthe foot through the insole and outsole to the ground.

2. A conductive shoe for personal wear comprising a conductive outsoledesigned for direct contact with the ground, said outsole being formedof relatively soft flexible material which presents a relatively highresistance to static electrical charges, an insole substantiallycoextensive with the inner face of said outsole, said insole comprisinga strip of relatively soft material including a ball portion, a heelportion and a connecting arch portion, there being openings extendingcompletely through the ball and heel portions of said striprespectively, an insert of relatively soft flexible conductive materialdisposed in each of said openings, said inserts also presenting arelatively high resistance to static electrical charges and beingconductively connected to said outsole, and a member formed ofconductive material electrically connecting said inserts.

3. A conductive shoe for personal wear, comprising a conductive outsoledesigned for direct contact with the ground, said outsole being formedof relatively soft flexible material which presents a relatively highresistance to static electrical charges, an inner sole substantiallycoextensive with the inner face of said outsole, comprising a strip ofrelatively soft material having an opening therein, an insert ofrelatively soft flexible conductive material disposed in said opening,said insert also presenting a relatively high'resistance to staticelectrical charges and being conductively connected to said outsole.

ANTHONY SIERS.

